<em># 定义</em>
<i>Duration</i> <s>A</s> = <b>Duration</b>(days: 1, hours: 1, minutes: 1, seconds: 1, milliseconds: 1, microseconds: 1); 		<em>// => 25:01:01.001001</em>
<em># 获取具体时间数</em>
<i>int</i> days = <s>A</s>.<b>inDays</b>;					<em>// 天数 => 1</em>
<i>int</i> hours = <s>A</s>.<b>inHours</b>;					<em>// 小时数 => 25</em>
<i>int</i> minutes = <s>A</s>.<b>inMinutes</b>;				<em>// 分钟数 => 1501</em>
<i>int</i> seconds = <s>A</s>.<b>inSeconds</b>;				<em>// 秒数 => 90061</em>
<i>int</i> milliseconds = <s>A</s>.<b>inMilliseconds</b>;		<em>// 毫秒数 => 90061001</em>
<i>int</i> microseconds = <s>A</s>.<b>inMicroseconds</b>;		<em>// 微秒数 => 90061001001</em>